1. Technical Field
The invention relates to communication systems, and more particularly, to systems that enhance speech.
2. Related Art
Communication devices may acquire, assimilate, and transfer speech signals. Many speech signals may be classified into voiced and unvoiced. In the time domain, unvoiced segments display a noise like structure. Little or no periodicity may be apparent. In the speech spectrum, voiced speech segments have almost a periodic structure.
Some natural speech has a combination of a harmonic spectrum and a noise spectrum. A mixture of harmonics and noise may appear across a large bandwidth. Non-stationary and/or varying levels of noise may be highly objectionable especially when the noise masks voiced segments and non-speech intervals. While the spectral characteristics of non-stationary noise may not vary greatly, its amplitude may vary drastically.
For this reason, there is a need for a system that may strengthen or enhance voiced segments without enhancing non-stationary noise. There is also a need for a system that enhances the periodic like structure of voiced segments in the presence of tonal interference.